Some time ago when I was studying the physiology of the human eye I noticed a curious concept called visual agnosia . This term refers to a disorder in the recognition, visual object, animal or person (more information than visual agnosia or Wiki
Neurology & Dementia ). Excerpt from a case of visual agnosia Element magazine:
"And yet there was something wrong. I watched as he spoke, was orientated towards me and yet there was something strange that did not fit at all ... it was difficult to achieve. I concluded that I dealt with their ears, but not with the eyes. Here, instead of looking, observing to me, "to look at me" in the normal way, performed fixations sudden and strange (in my nose, my right ear, then down to the chin, then went up to my right eye) as if captured, as if studying even those individual items, but not entirely see my face, his expressions variables, "me" as a whole. I'm not sure it came time to fully understand this, just had a disturbing feeling of something strange, a failure in the normal relationship of gaze and expression. I saw, I recorded, and yet .....
- What's wrong with you? I asked at last.
"I think nothing," he replied with a smile but all I say something wrong in my view.
[...] and then excused to save the ophthalmoscope, I let him put on his shoe. I checked surprised after a minute that he had not.
- Want to help? I asked.
- Does it help? "Help who?
-Help you to put the shoe.
"Oh, yes, said I had forgotten the shoe, and said, sotto voce:" Does the shoe? Does the shoe?
seemed perplejo. "The Shoe" I repeated. You should wear it.
kept looking down, but not the shoe, with intense concentration, but inappropriate. Finally laid his eyes on his own feet.
- This is my shoe, right?
Had I misheard? Had he been wrong?
"It is the view," he explained, and directed his hand to his foot. This is my shoe, right?
"No, it is not. That is the foot. The shoe is there.
- Ah! I thought it was the foot.
kidding? Was I crazy? Was he blind? If that was one of his "strange error" was the strangest error I encountered in my life.
seemed also decide that the visit was over and started looking around for his hat. He reached out and grabbed his wife by trying to put it on the head. He seemed to have mistaken his wife for a hat! She seemed to be accustomed to those mishaps.
However, despite the obvious visual agnosia Mr. P., he had found a way to keep functioning reasonably continued giving lessons and, although he could not recognize her students for the face or on the bus by their form, was perfectly capable, just hearing the voice of a person or the noise produced by a motor, either immediately recognize and identify an approaching bus. We have in this case an alteration of the superior processing of information. What seems to have lost Mr. P. is part of the process of analysis and visual integration that lead us to recognize an object or a person. The face recognition seems a particularly complex and particularly labile. Think when we look at someone from far away, like a classmate we had not seen for several years and who immediately recognize, among several people, only to see it. How is this possible? How does the brain differentiate the characteristics of a person around you that are so similar? How many different people can you recognize at a glance? This is an example of the extraordinary capacity of analysis with neural networks in the visual cortex. Face recognition plays an important part in the neocortex of the areas visual and appear to be groups of neurons whose activity is closely related to the recognition of faces. These cells would, after other cortical areas have been identified the main features of a face, move to a process of integration and comparison with prior information to identify the individual concerned. The operation of these networks and neural circuits is shown in cases of brain damage, as there are injuries that can affect only the ability to recognize faces without changes in other intellectual functions. The loss of the ability to recognize faces is called prosopagnosia and, among others, was one of the symptoms of deep suffering visual agnosia Mr. P. Just modularity in the organization of the central nervous system is what determines that, just as sick of ulcer, heart or kidney failure and survived thanks to the adaptive changes experienced by the body and which constitute what we call disease, also can suffer from prosopagnosia of amnesia or the inability to name objects, and the individual adapts, self resets with astonishing capacity to their new condition. Fortunately the self is not an indivisible entity, is perfectly capable of being divided and limited, how far is divisible?, Do not know, know the minimum unit necessary to maintain the identity and self-awareness and sustain an independent intellectual life, able to think logically and fill the existing presence. "
Well, for this disorder that some people there counterbalance the perception of form through movement . This phenomenon was discovered by Grossman and Blake in 2001 and was a breakthrough not only within laboratories, but the outside world.
subjects but not can visually recognize objects can perceive the actions performed (such as someone who shared simulates a deck of cards or wear a wristwatch.) They may even recognize a known gait if they can not recognize his face or catch a ball when they are thrown (but being this static are incapable). Neil R. Carlson, Physiology of behavior Chapter 6: Vision, 215-216
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